text: The use of cell encapsulated microcapsules towards the treatment of several forms of cancer has shown great potential. One approach undertaken by researchers is through the implantation of microcapsules containing genetically modified cytokine secreting cells. An example of this was demonstrated by Cirone et al. when genetically modified IL-2 cytokine secreting   non-autologous mouse myoblasts implanted into mice showed a delay in the tumor growth with an increased rate of survival of the animals. However, the efficiency of this treatment was brief due to an immune response towards the implanted microcapsules. 
  Another approach to cancer suppression is through the use of angiogenesis inhibitors to prevent the release of growth factors which lead to the spread of tumors. The effect of implanting microcapsules loaded with xenogenic cells genetically modified to secrete endostatin, an antiangiogenic drug which causes apoptosis in tumor cells, has been extensively studied. However, this method of local delivery of microcapsules was not feasible in the treatment of patients with many tumors or in metastasis cases and has led to recent studies involving systemic implantation of the capsules.
  In 1998, a murine model of pancreatic cancer was used to study the effect of implanting genetically modified cytochrome P450 expressing feline epithelial cells encapsulated in cellulose sulfate polymers for the treatment of solid tumors. The approach demonstrated for the first time the application of enzyme expressing cells to activate chemotherapeutic agents. On the basis of these results, an encapsulated cell therapy product, NovaCaps, was tested in a phase I and II clinical trial for the treatment of pancreatic cancer in patients and has recently been designated by the European medicines agency (EMEA) as an orphan drug in Europe. A further phase I/II clinical trial using the same product confirmed the results of the first trial, demonstrating an approximate doubling of survival time in patients with stage IV pancreatic cancer. In all of these trials using cellulose sulphate, in addition to the clear anti-tumour effects, the capsules were well tolerated and there were no adverse reactions seen such as immune response to the capsules, demonstrating the biocompatible nature of the cellulose sulphate capsules. In one patient the capsules were in place for almost 2 years with no side effects.
  These studies show the promising potential application of cell microcapsules towards the treatment of cancers. However, solutions to issues such as immune response leading to inflammation of the surrounding tissue at the site of capsule implantation have to be researched in detail before more clinical trials are possible.